Studies On The Residue And Elimination Of Oxolinic Acid In Cultured Flounder (Paralichthys Oliuaceus)

Oxolinic acid (OA) is a synthetic antibacterial agent that belongs to the quinolone group. It is widely used in many countries's aquaculture industry because of its low toxicity and satisfactory activity against both Gram-negative and some Gram-positive bacteria. There are no strict MRLs before, but the MRLs in Japan and Korea have being emended much lower recently. So the relative researches of OA have become more and more important.There are little studies on OA in our country. The analytical method can't meet the requirement of new MRLs. The pharmacokinetics of fishery drugs, especially OA in our country are scarce. So a series of experiments were carried out for studies on OA analytical method and pharmacokinetics to denote the residue and elimination of OA in cultured flounders.A HPLC method for the analysis of the OA residue in fishery product was optimized though comparing the relative researches. The drug was extracted from tissues with dried ethylacetate. After homogeneity and centrifuge, the extract was evaporated to dryness and quantitatively dissolved with mobile phase. Then the solution was treated with n-hexane to remove the fat. Then the residue was analysed by HPLC with a fluorescence detector (Ex325nm/Em369nm) using 0.02mol/L phosphoric acid+ acetonitrile +tetrahydrofuran(69:16:15) as mobile phase. Through comparing the different kinds aquatic products which fortified at different levels, the average recoveries are between 79%～93%. The relative standard deviations are all lower than 10%. The instrument detection level and method detection limit was 1μg/kg and 5μg/kg, respectively. The method is better than the researches using similar detector in our country and can meet for the pharmacokinetics study.In the 21士1℃seawater, single(90mg/kg weight) and multiple(40mg/kg weight , twice a day for 5days) dose of OA was administered orally to...